1. Field of the Invention
The invention relates to an electrical switching device, preferably a high-frequency switching device.
2. Related Technology
A switching device of this kind is described in DE 101 03 814 A1. This switching device is used in particular for switching a current conduction for a high-frequency calibration line through various attenuation elements. For this purpose, it provides an oblong and preferably-flat switching element, which can be moved transversely to its longitudinal direction by an adjustment element. In this context, a contact surface at its one end is brought optionally into contact or out of contact with a fixed-contact surface. In the contact position, the conduction of electrical current to the contact surfaces is dependent, among other factors, upon the mutual disposition of the contact surfaces and the fixed-contact surfaces. Contamination or particles can substantially impair the current conduction, especially if the contamination and/or particles consist of electrically non-conductive material.
An interference-free current conduction is particularly important in the case of calibration lines, which are used as a reference for attenuation adjustments, for example, of signal generators or network analysers. Calibration lines provide, for example, several four-pole switching devices arranged in series with equal and constant surge impedance at the input-end and output-end and, in each case, with adjustable, calibrated attenuation and therefore also with a precise level.
In the case of the known high-frequency electrical switching devices, as they are typically used, for example, in high-frequency calibration lines, the lateral switching movement of a switching element through an application of an external mechanical force is achieved by plungers, which press laterally against the switching element thereby moving the latter. As a result of the lateral, rotary movement, carried out by the switching element and the linear pushing movements of the plungers provided on both sides of the switching element, sliding movements occur in the contact region of the plungers and the switching element. These movements cause abrasion as a result of the associated friction. In particular, if the switching device provides an enclosed switching chamber, the risk of a contact impairment resulting from the abrasion caused by the friction is particularly great, because the abraded particles remain in the switching chamber. But even in the case of an open switching chamber, there is also a risk that the abraded particles could enter between the contact surfaces and impair the electrical contact. Moreover, the plungers can have a negative influence on the high-frequency behavior.